JEE Main · 2023 · 25 Jan 2023 · Shift 2 · Modern Physics

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The energy levels of an atom is shown is figure. Which one of these transitions will result in the emission of a photon of wavelength 124.1 nm ? Given (

h = 6.62 \times 1 0^{- 34} Js

)

(A)B
(B)A
(C)C
(D)D✓ Correct

Answer: (D)

Solution

The emitted wavelength fixes the energy gap through

Δ E = \frac{h c}{λ}

, and with

h c = 1241 eV nm

a wavelength of

124.1 nm

corresponds to

Δ E = \frac{1241}{124.1} = 10 eV

. Reading the diagram, the drop from the

0.0 eV

level to the

- 10.0 eV

level is the only transition spanning

10 eV

. The

124.1 nm

photon comes from the transition ending on the lowest level, marked D in the diagram.

JEE Main · 2023 · 25 Jan 2023 · Shift 2 · Single correct option

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